It has recently been discovered that a certain class of 2-haloacetanilide herbicides are particularly useful in safely controlling hard-to-kill perennial weeds such as quackgrass, nutsedges and many others in the presence of a variety of crops including cotton, corn, and soybean. This new class of herbicides is described and claimed in Belgium Patent 887,997 issued September 18, 1981. A particularly effective herbicide within this class is N-(ethoxymethyl)-2'-(trifluoromethyl)-6'-methyl-2-chloroacetanilide.
The present invention relates to chemical intermediates in the production of compounds within this new class of herbicides. The present invention also relates to a process for preparing these chemical intermediates. This process generally involves nitration of substituted benzotrifluoride compounds.
Electrophilic substitution such as nitration, sulfonation, etc. of various types of substituted benzene compounds is known in the art. It is also known that substituents on the benzene ring can affect both the reactivity and orientation of electrophilic substitution. Certain substituents can increase the reactivity of the benzene ring by donating electron density to the ring inductively or by resonance. Other groups withdraw electron density from the ring and thus reduce the reactivity of the ring.
Ring substituents can either direct electrophilic substitution at the ortho, para, or meta positions. With a plurality of substituents, the substituents can either reinforce or oppose each others directive influence. Activating substituents generally prevail over deactivating substituents. Generally, electrophilic substitution onto a benzene ring having a plurality of substituents which individually direct substitution at alternative open positions on the ring will result in a mixture of substitution products.
It is an object of the present invention to provide new intermediate compounds useful in the production of compounds within a new class of 2-haloacetanilide herbicides.
It is another object of this invention to provide a process for preparing some of these new intermediate compounds.
It is another object of this invention to provide a new aromatic nitration directing system.
Other objects and advantages will become apparent from the following disclosure.